In U.S. Pat. No. 6,000,897 of Desjarlais issued Dec. 14, 1999 is disclosed a machine for inserting a plastic coil into aligned holes at the edge of a book for binding of the book. Such coils are formed of a plastic filament which is wound into a helical coil. Coils of different diameters can be selected for different thicknesses of book with the diameters commonly available lying in the range 6 mm to 30( ) mm.
Also in U.S. patent application Ser. No. 10/449,713, filed Jun. 2, 2003 now issued as U.S. Pat. No. 7,246,982 issued Jul. 24, 2007 and corresponding Canadian application, filed May 27, 2003, Ser. No. 2,429,874 both entitled BOOKBINDING COIL INSERTION MACHINE is disclosed an improved arrangement for the same purpose.
Both of these patents provide an arrangement for inserting the coil into the book which includes end cutters for cutting and crimping the ends of the inserted coil so that the coil is cut to length and simultaneously the cut end is bent at an angle to the length of the filament forming the coil so that the coil is held in place in the end holes of the edge of the book. The machine disclosed is automated and is thus generally more suitable for longer production runs where the cost of the machine can be justified.
In other lower cost situations such as in smaller offices or in low production runs it is common to use either manual insertion of the coil or to use a roller or belt drive system to assist in coil insertion where the operator holds the book in place at the drive system till the frictional contact between the coil and the drive moves the coil to the required location. Such devices do not include a cutting and crimping device since the complexity is not suitable for the low cost drive system.
In order to effect the cutting and crimping action, therefore, the operator can use a manual cutting tool in the form of a pair of specially designed pliers. However these are awkward to use and sometimes ineffective if not properly located and operated relative to the coil and are disliked by the operators.
Previous devices have been provided for receiving the book and coil and for cutting and crimping the ends of the inserted coil. The operator holds the book in place and the device has a cutter device which is driven by suitable motive force such as pneumatics to effect the cutting action.
One machine of this type is manufactured by Renz of Heuback Germany which is known as “Coil Cut”. This device is shown in an operating manual and comprises a pair of cutting devices at spaced positions across the machine for engaging the respective ends. Two V-shaped guides are located just inboard of the cutting devices such that the outside cylindrical surface of the coil is placed to sit in the V. These act to center the coil relative to the cutting device. Also, the height of the V-shaped guide relative to the cutting device is adjustable to accommodate different diameter of coil so as place the position of the filament to be cut in the knife at a required location. It will be appreciated that larger diameter coils require a longer crimped portion relative to smaller diameter coils to prevent the coil from being pulled through the first hole in the book and moving from its required position. This change in length of the crimping action can be obtained by moving the position of the filament relative to the knife so that the cutting action takes place at a different location on the cutting device. The cutting device is then shaped so that the different location on the cutting device causes the length of the crimped portion to be automatically cut to the require length.
The Renz machine is limited in coil size to the range 6 to 20 mm as clearly stated in the Manual. It cannot therefore operate with coils in the range 20 to 50 mm which are commonly available and thus suffers from this clear and severe restriction.
Also the guidance of the coils in the V-shaped guide is of limited effectiveness requiring careful attention by the operator to ensure that the coil is in the required location.
Another machine of this type which is currently available is that manufactured by Marlon Inc of Boise Id. This is shown in an Operator's Manual and uses a similar arrangement to that described above. In this arrangement the side of the book is placed on a support plate the height of which is adjustable relative to the position of the cutting device so as to locate the position of the coil in the cutting device.
This machine is operable with coils of diameters 6 to 50 mm but only by purchasing and inserting three replacement cutting devices for different parts of the range. Thus there are three cutting devices where a first operates in the range 6 to 7 mm, a second in the range 8 to 25 mm and a third in the range 12 to 50 mm. These three devices are expensive and complex to replace and set up. Also the placement of the book against a plate does not itself accurately locate the coil leaving possibility for faulty crimping action due to the misplacement of the coil. Hold down devices are proposed to be added for the small size coil since misplacement is more problematic at the small diameters.